HESI A2 Biology Practice Test 2024

Correct Answer: C

Rationale: The correct answer is C: Vacuoles. Plant cells have vacuoles that function as storage for nutrients, waste disposal by containing and breaking down unwanted materials, and protection by regulating turgor pressure to maintain cell structure and protect against external stressors. Nucleus (A) is the control center of the cell, mitochondria (B) are responsible for energy production, and ribosomes (D) are involved in protein synthesis, none of which directly fulfill the functions described in the question.

Correct Answer: B

Rationale: The correct answer is B: Lipids. The plasma membrane is primarily composed of lipids, specifically phospholipids, which form a lipid bilayer. This structure provides the membrane with its selective permeability properties. Proteins are also present in the membrane, but they are not the primary composition. Carbohydrates are found on the outer surface of the membrane for cell recognition and signaling. Nucleotides are the building blocks of nucleic acids and are not a major component of the plasma membrane.

Correct Answer: B

Rationale: The correct answer is B: Eukaryotic. Animal cells are eukaryotic cells because they have a defined nucleus that houses the genetic material. This nucleus is surrounded by a membrane, along with other membrane-bound organelles like mitochondria and endoplasmic reticulum. Prokaryotic cells (Option A) lack a true nucleus and membrane-bound organelles. Plant cells (Option C) have similar characteristics to animal cells but also have additional features like a cell wall and chloroplasts. Bacterial cells (Option D) are prokaryotic cells and differ significantly from animal cells in structure and function.

Correct Answer: B

Rationale: The correct answer is B: Active Transport. Active transport moves substances across the cell membrane against the concentration gradient, requiring energy (usually in the form of ATP). This process is crucial for maintaining cellular homeostasis and allowing the cell to accumulate essential molecules. Passive transport (A) does not require energy and moves substances along the concentration gradient. Facilitated diffusion (C) is a type of passive transport that involves the use of transport proteins to move specific molecules across the membrane. Osmosis (D) is the movement of water across a selectively permeable membrane, also considered a type of passive transport.

Correct Answer: B

Rationale: The correct answer is B: Mitochondria. Mitochondria are known as the powerhouse of the cell as they produce energy through the process of respiration. They contain enzymes responsible for converting nutrients into ATP, the energy currency of the cell. The nucleus (A) is responsible for storing genetic material, Golgi Apparatus (C) is involved in protein processing and packaging, and Chloroplasts (D) are responsible for photosynthesis in plant cells, not respiration.